Date of Award


Document Type


Degree Name

Master of Science in Environmental Engineering and Science


Department of Systems Engineering and Management

First Advisor

Willie F. Harper, Jr., PhD.


This research investigated the germination and outgrowth of Bacillus globigii in the presence of ammonia in laboratory scale experiments. Germination was measured by monitoring the release of dipicolinic acid, an organic compound present in bacterial spores, while outgrowth was measured using phase-bright microscopy and semi-automated counting procedures. The ammonia-N concentrations investigated generally did not cause statistically significant differences in the initial 1-hr germination rates or the average 3-hr outgrowth rates of Bacillus globigii spores in batch style experiments. The average 1-hr germination rates observed in the absence of ammonia-N was 0.0258 hr-1 for the water and buffer controls and between 0.00732 and 0.0127 hr-1 with synthetic feed over a range of ammonia-N concentrations. The 3-hr outgrowth rates were 0.0761 and 0.1821 hr-1 for the buffer control and positive control respectively but it cannot be concluded that ammonia-N was responsible for this difference. Ammonia-N was correlated with subtle but statistically significant impacts over a 7-day period. The sodium bicarbonate present in the synthetic feed likely caused inhibition of the germination rates as well as the shape of the 7-day germination profiles. To this author’s knowledge, this study is the first to investigate the effect of ammonia-N on the germination and outgrowth of Bacillus globigii in concentrations typically found in wastewater treatment plants and in the presence of synthetic feed.

AFIT Designator


DTIC Accession Number